Development of a new CAD-method for Tool CAE-analysts at Gestamp HardTech

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MASTER'S THESIS

Development of a new CAD-Method for

Tool CAE-analysts at Gestamp HardTech

Erika Andersson

Zeinab Al-shatrawi

2016

Master of Science in Engineering Technology

Industrial Design Engineering

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Acknowledgement

This report is the final project that is included in the Master of Science degree in industrial design engineering with the major in Product Design at Luleå University of Technology. It was conducted at Gestamp HardTech R&D in Luleå. Our thesis was developed with the knowledge that were gathered from our education and expertise found at Development TechCenter (DTC).

We would like to thank everyone that contributed to our project at DTC for their engagement, support and valuable opinions during the project. Many thanks to our supervisor Stefan Sandberg at DTC who welcomed us to the department. He supported us with knowledge in the subject and helped us throughout the thesis.

Our sincerest thanks to our supervisor Peter Jeppsson at Luleå University of Technology for his expertise in the area and inspiration for the CAD-method and automations. He was supportive, engaged in our work and encouraged us to seek help whenever needed.

Luleå June, 2016

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Abstract

This project is a Master of Science thesis in industrial design engineering at Luleå University of Technology. It was conducted by Zeinab Al-shatrawi and Erika Andersson in cooperation with Gestamp HardTech R&D in Luleå during the spring semester of 2016.

Gestamp HardTech is a world leading company in the press-hardening technology. They manufactures and delivers car components such as side impact beams, bumpers, A-pillar and B-pillar. They also develop and manufacture the production tools for the components. Tool CAE-analysts at the Research and Development Center in Luleå develops components and tools. Their work consists of modelling and simulations in order to create forming specifications and tooling specifications for the products. The Tool CAE-analysts either uses the product development software NX or CATIA V5. The Tool CAE-analysts that uses CATIA V5 share a common CAD-method and uses automated features to speed up and structure their work. There are no common CAD-method or automated features in NX so each Tool CAE-analyst has created their individual CAD-method.

The objectives in this project was to develop a new common CAD-method and to identify suitable features to automate that are beneficial for the Tool CAE-analysts that uses NX. The automations allows the product development software to create the work. The purposes of the new CAD-method and automations are to structure and standardize their work process. Standardization in their work can increase the quality, make their development process more time-efficient and facilitate their teamwork.

The project started by studying the assignment and analyzing the background. This information was used to plan and structure the process. The project continued with a literature study that included studies of previous theses at Gestamp HardTech and studies of the areas industrial design engineering, method objectives, organizing tools in NX and automation tools in NX. The literature study continued throughout the whole project process.

Tool CAE-analysts were observed and interviewed while they worked on projects. The purpose was to understand the context, the needs of the users and each Tool CAE-analysts CAD-method. The steps in the CAD-methods were represented in Hierarchal task analysis models in order to evaluate the different CAD-methods. The evaluation was intended to identify advantages, disadvantages and common denominators in their work. The project followed with brainstorming and future workshop sessions to create ideas for the common CAD-method and automations. The Tool CAE-analysts participated in the Workshop to share their ideas. The ideas were developed into a final draft of the CAD-method and a final list of automations.

This thesis resulted in a first draft of a common CAD-method, a template with a standard setup of feature groups and a manual with instructions on how to follow the CAD-method. The project also resulted in a list with suggested automations to develop. The list included information on the purpose of every automation, the commands that can be used to create them and important parameters to take into consideration when creating the automations.

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Sammanfattning

Den här rapporten behandlar ett examensarbete i Teknisk design på Luleå tekniska universitet. Det var utfört av Zeinab Al-shatrawi och Erika Andersson i samarbete med Gestamp HardTech R&D i Luleå under våren 2016.

Gestamp HardTech är ett världsledande företag inom presshärdningsteknik. De tillverkar och levererar bilkomponenter så som sidokrockskydd, stötfångare samt A-stolpar och B-stolpar. De utvecklar och tillverkar även verktygen för tillverkning av komponenterna. Formningsanalytikerna på forsknings och utvecklingsavdelningen i Luleå tar fram komponenterna och verktygen. Deras arbete består av modellering och simuleringar för att ta fram formningsspecifikationer och verktygsspecifikationer för produkterna. Formningsanalytikerna använder sig antigen av CAD-programmet NX eller CATIA V5. De som använder CATIA V5 följer en gemensam metodik och har automatiserade features som de kan använda för att effektivisera och strukturera arbetet. Det finns ingen gemensam metodik eller automatiserade features för de som arbetar i NX vilket har lett till att alla formningsanalytiker har skapat sin egen metodik.

Syftet med projektet var att utveckla en gemensam CAD-metodik och att ta fram förslag på automatiseringar som kan vara fördelaktiga att skapa i NX. Automatiseringarna ska förenkla arbetet genom att låta produktutvecklings program att utföra arbetet. Resultatet ska leda till att arbetet blir mer strukturerat och standardiserat och det ska i sin tur leda till att kvalitén höjs, att arbetet går snabbare och att deras samarbete förbättras.

Projektet inleddes med att studera uppgiften och bakgrunden till den. Studien användes till att planera och strukturera processen i projektet. Projektet fortsatte med en litteraturstudie som inkluderade utförda examensarbeten på Gestamp HardTech och studier av forskningsområdena; Teknisk Design, metodik, organiseringsverktyg i NX och automatiseringsverktyg i NX.

Observationer och intervjuer utfördes med formningsanalytikerna samtidigt som de arbetade med projekt. Syftet var att skapa en förståelse för kontexten, behoven och de olika CAD-metodikerna. Varje CAD-metodik representerades i en HTA-modell och modellerna användes sedan till att utvärdera och identifiera fördelar, nackdelar och gemensamma nämnare hos respektive metodik. Därefter utfördes brainstorming och future workshops för att ta fram idéer till den gemensamma CAD-metodiken och automatiseringar. Formningsanalytikerna var delaktiga i workshopen för att de skulle få möjlighet att dela med sig av sina åsikter och idéer. Slutligen användes idéerna till att ta fram och utveckla ett förslag på en gemensam CAD-metodik och ett förslag på automatiseringar. Projektet resulterade i ett första utkast på en gemensam CAD-metodik, en mall med en standard uppsättning av Feature Group och en manual med instruktioner på hur CAD-metodiken kan följas. Arbetet resulterade även i en lista med förslag på automatiseringar. Listan innehöll information om syftet med varje automation, kommandon som kan användas för att skapa automatiseringar samt viktiga parametrar som ska has i åtanke när automatiseringarna skapas.

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List of figures

Figure 1. Placement of body structural components in a car (Used with permission from Gestamp HardTech).

Figure 2. Example of a tool concept that comprise upper die, lower die, blank, pins and split curves. Figure 3. The phases in this thesis project.

Figure 4. Analysis of the CAD-methods that are listed in HTA-models. Figure 5. Describing the two sessions in the ideation phase.

Figure 6. Sticky notes placed on a board to be categorized. Figure 7. The phases in the future workshops sessions.

Figure 8. The participants in the first workshop session during the critique phase. Figure 9. The steps to create the template and manual are described in a chart. Figure 10. Tool surfaces in yellow for a B-pillar.

Figure 11. Example of a setup of a tool concept.

Figure 12. The first sketch is for a slot shaped hole and the second is for a hole shaped as a dog bone.

Figure 13. Examples of collars created on the out of die model.

Figure 14. The features and feature groups created in the first observed Tool CAE-analysts work. Figure 15. The history tree of the second observed Tool CAE-analysts work.

Figure 16. The groups created in the third observed Tool CAE-analysts work.

Figure 17. The groups and feature groups created in the fourth observed Tool CAE-analysts work. Figure 18. Example of an automation in CATIA V5.

Figure 19. The same features as in the first part navigator is embedded to the feature group in the second part navigator.

Figure 20. Layer setting dialog window

Figure 21. The layer an object resides on is displayed in the layer column in the part navigator. Figure 22. Standard setup of feature groups in the template.

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Nomenclature

Blank A piece of metal ready to be press-hardened into finished object.

CAD Computer Aided Design

CATIA V5 Product development software from Dassault Systémes.

Collar Refers either to a section of a shaft or rod having a locally increased diameter, or an upper rim of a hole to provide a bearing seat or a locating ring.

DTC Development TechCenter

Feature Refers to a region of a part that contains interesting geometric or topological properties.

FS Forming Specification contains information within the company about the design after simulation.

Movable Pads A part of the tool that forms the blank in sequences.

NX Product development software from Siemens PLM Software.

Out of die A part that mimics the geometry of the blank when it comes out from the press-hardening process, before post operations.

Part Refers to a model of a single component in CAD.

Part Navigator Detailed, graphical (history) tree of a part in NX.

PID Part identification, every part in the tool package has a PID number and colour.

Pin Refers to centring pin, process pin or collar pin in a tool setup.

PA Product Assessment contains information within the company about the components design and operation layout.

PR Product Remarks contains information sent to the customer about design, forming feasibility, design change input and tolerance proposal.

Split Surface Surface used to split tool surfaces to resemble movable pads.

Draw bead Controls the material flow of the blank.

Tool CAE-analyst Engineer at DTC responsible for FS and TS.

TS Tooling Specification contains information about the tool for the tooling department.

Tool concept Forming information that the Tool CAE-analysts send to the tool designers. It consists of surfaces for lower and upper die, split lines, blanks, pins and holes.

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1 Introduction

This project aims to develop a new common CAD-method and to identify suitable automations. An automation will read an input and create a part without human intervention. The automations aims to benefit the Tool CAE-analysts in their work. The new CAD-method aims to create a standard for organizing the Tool CAE-analysts’ work in order to facilitate their teamwork. The project is a 30 credits Master of Science thesis in industrial design engineering at Luleå University of Technology. It was conducted in collaboration with TechCenter at Gestamp HardTech during the spring semester of 2016.

BACKGROUND

Gestamp HardTech is a world leading company in the press-hardening technology. It is part of the Spanish owned company Gestamp Automoción, which is a group of companies located around the world specialized in producing metal components and structural systems for the automotive industry.

Gestamp HardTech’s press-hardening technology was originally developed in Luleå 1974. Press-hardening technology allows the manufactured products to be light and strong with complex geometry. Gestamp HardTech designs, manufactures and delivers safety components such as side impact beams, bumpers, A-pillar and B-pillar, Figure 1. They also develop and manufacture the production tools for the components.

The Research and Development Center (R&D) in Luleå develops components and tools in close cooperation with customers such as Ford, GM, VW, Volvo and BMW. The development process consists of modelling and simulations to ensure that products meets all requirements. The product development software used in the department are software CATIA V5 and NX. There are two engineering categories at Development TechCenter; Product engineers and Tool CAE-analysts. They are responsible for product remarks, product assessment, forming specification and tooling specification of the design.

Side Impact Beams Bumper Beams

Cross & Side Members A & B Pillar Reinforcement Waist Rail Reinforcement

Figure 1. Placement of body structural components in a car (Used with permission from Gestamp HardTech).

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CONTEXT

Tool CAE-analysts are responsible for making FS and TS. The forming simulations timeline include to:

 Set up a forming simulation.  Run the simulation.

 Analyse the forming result.

 Change parameters and restart the forming simulation.  Forward CAD-models to the tool designers.

The forming information is called a tool concept and it consists of surfaces for the lower and upper die, blank, pins, holes and split curves, Figure 2. The development of a tool concept is an iterative process of forming simulations until the forming setup generates desired product quality regarding thinning and thickening levels.

Figure 2. Example of a tool concept that comprise upper die, lower die, blank, pins and split curves.

Tool CAE-analysts are either using NX or CATIA V5 as their product development software. The Tool CAE-analysts that uses CATIA V5 uses a start model and uses automated features for frequent operations in order to speed up and structure their work. There are currently no start model or automated features developed in NX so the developers that uses NX have come up with their own individual CAD-method. It can therefore be hard to understand and continue another person’s work. The Tool CAE-analysts that uses NX should also have a common CAD-method and automated features to structure and speed up repetitive work.

PROJECT STAKEHOLDERS

Primary stakeholders in this master thesis are the Tool CAE-analysts at TechCenter that works in NX. The outcome of this project will affect their work and their needs should therefore be taken into consideration. The CAD-method that is developed in this project is meant to be used by the Tool CAE-analysts, so the result should therefore be accepted by all of them. It is important to understand their work in order to find repetitively used features that are beneficial to automate. The result of this project is expected to structure their work and to make it more time-efficient

Upper die

Lower die Blank

Split curves Pin

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PROJECT OBJECTIVES AND AIMS

The objective of the project are to develop a common CAD-method in NX and to identify features to automate that would benefit Tool CAE-analysts in their work. The common CAD-method will organize the work for the Tool CAE-analysts that use NX and it will be similar to the one in CATIA V5. It intends to help the Tool CAE-analysts to easily navigate and understand each other’s CAD-model, which will reduce time spent on searching and understanding different CAD-models and remodelling from scratch. The suggestions of features to automate intends to help the user with repetitive and time consuming work. A common CAD-method gives quality assurance of their work and makes it more likely that the work process will look the same for all the Tool CAE-analysts. The project aims to deliver a common CAD-method that can be used by the Tool CAE-analysts that uses NX. The CAD-method is supposed to suggest how to structure the work. The project also aims to propose how their work can be automated and how the automations can function. The CAD-method will be described in a manual and the automations will be suggested in a list.

The research questions of this project are:

 What are the needs of the Tool CAE-analysts regarding their work process when they develop a tool concept?

 How can a common CAD-method be designed for all Tool CAE-analysts that uses NX, so that

- it meets their needs

- they all organize their work in a similar way in NX

- they organize their work in a similar way as in CATIA V5?

 Which parts of the Tool CAE-analysts work are repetitive and time-consuming and would be beneficial to automate in NX?

PROJECT SCOPE

The scope and delimitations are set as boundaries to control the range of the thesis. The delimitations are:

 The Tool CAE-analysts’ different CAD-method will be analysed in both CATIA V5 and NX and the new CAD-method will be developed for NX.

 The common CAD-method is adapted to the work done by the Tool CAE-analysts at DTC. It is built from analysing the CAD-methods in the department which means that CAD-methods used outside DTC are not included in this thesis.

 The work that is included in the new CAD-method are operations that are used to create a tool concept. It includes work done after importing the customer CAD and before

exporting and sending the tool concept to the HardTech Tooling department.  Import and export of CAD-model between different programs is not covered in this

thesis.

 The optimization routine, when adapting the geometry after the results from the simulations, is included but not the simulations.

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THESIS OUTLINE

This section gives a brief introduction to the chapters in the thesis.

Chapter 1, Introduction

This chapter describes the background to the assignment, context, stakeholders, objectives and aims and the scope of the project.

Chapter 2, Theoretical framework

This chapter contains the literature study that was conducted during the thesis. It present information on the theoretical areas that have been necessary to understand in order to complete this master thesis.

Chapter 3, Method and Implementation

The third chapter presents the methods that were used to conduct this master thesis in chronological order. The chapter describes the process that was used through the project and a description of each phase and methods. The description includes information about how they are used in the project and why.

Chapter 4, Result of Context Immersion

Chapter four presents the results from the context immersion phase. It presents the work process, the users’ needs and the standards in their work.

Chapter 5, Result of Analysis

This chapter contains the results from the Analysis phase. This section describes the distinctive ways of organizing with groups and naming. The common denominators and repetitively used features in the work process are also described.

Chapter 6, Result of Ideation

The chapter presents the results of the ideation phase. Ideas on the common CAD-method is presented in the chapter. It includes ideas on the order to do each part of the work and how to organize and name objects. A list with automation is also presented in this chapter. The list includes descriptions for what the automations are and what they do.

Chapter 7, Result of Detail Design

Chapter seven contains the results from the final phase. It starts by presenting the final draft of the common CAD-method and then the final result of the suggested automations.

Chapter 8, Discussion

This chapter discusses the result of the project, the used methods, the process and ends by recommendations on future work.

Chapter 9, Conclusion

The final result of this master thesis is described in this chapter in relation to the project objectives and aims. It will also include answers to the research questions set in the beginning of the project.

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2 Theoretical framework

This chapter contains the literature study conducted during this master thesis. The theories in this chapter have been studied in order to complete this master thesis. The chapter starts with a brief introduction to the area industrial design engineering and follows with information that was conducted about the purpose of creating and implementing a methodology. The chapter also includes guidelines for how to design and an overview of the tools and commands in NX for organizing and automating. The research areas in this chapter are industrial design engineering, user-centred design, methodology objectives, organizing tools in NX, and automation tools in NX.

INDUSTRIAL DESIGN ENGINEERING

The theoretical basis of this thesis lies within areas of industrial design engineering. Industrial design engineering is a broad subject area. De Vere, Melles & Kapoor (2010) describes the area as a combination of industrial design and engineering. An industrial design engineer should have a holistic view that is needed in order to develop products, processes or services.

Krippendorff (1989) describes design as making sense of things. Norman (2002) describes the profession of an industrial designer as creating and developing concepts that optimize the value, function and appearance. The design should be beneficial for both the user and manufacturer. Ulrich & Eppinger (2011) means that the success of most firms depends on the ability to identify the needs of customers in order to create products, system and processes that meets these needs.

Johannesson, Persson & Pettersson (2004) means that an industrial design engineer focuses on both the design and construction. It is important that an industrial design engineer designs with regard to the manufacturing, so that the ideas can become possible to implement (Norman, 2002). An industrial design engineer should also take into consideration that badly engineered products could hurt humans (Pugh, 1990). In order to avoid this risk, a designer need to understand the knowledge that is contained within engineering. Pahl & Beitz (1996) means that the profession of industrial engineering design calls for knowledge in mathematics, physics, chemistry, mechanics, production engineering, materials technology and design theory. An industrial design engineer has also knowledge in CAD. The automotive industry uses CAD as a tool to develop products. Boedin (2014) means that an industrial design engineer has enough knowledge in CAD to be able to improve the development process in the automotive industry. It is this knowledge that will be used throughout this thesis to fulfil the objectives.

USER-CENTRED DESIGN

Design is not always intuitive and at times it leaves the user frustrated and unable to complete a simple task. User-centred design (UCD) is an approach that aims to create interfaces, products and services that are applicable, appropriate and accessible to as many users as possible (Wilkinson & De Angeli, 2014). UCD is a broad term and it describes design processes in which users influence the design (Abras, Maloney-Krichmar & Preece, 2004). Inviting the users to participate in the design process attempts to better understand the users in order to create more appropriate and user friendly products (Wilkinson & De Angeli, 2014). One way of involving the user is by consulting them and taking their needs into consideration (Abras et al., 2004).

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Chammas, Quaresma & Mont’Alvão (2015) means that the UCD approach intends to increase the acceptance and productivity of interactive systems and also reduce errors and hours of support and training. The approach also intends to provide the best responses from the use or anticipated use of a product, system or service. Chammas et al., (2015) lists a number of principles that should be considered when the goal is to design an interactive system centred on users and their needs. Some of these principles are that the design should be adapted to the context and the users should be involved throughout the development process. Another principle is that focus should lie on the users to minimize the risk that the system does not reach the requirements that meets their needs.

METHODOLOGY

The requirements in terms of functionality and quality of the products increase due to the strong competition in today’s market (Bodein 2014). This enables more complex product processes whereas the product development time needs to be decreased. It is possible to meet these constrains by creating an adapted methodology. Long and complex design activities are characteristic in the automotive industry. It is important to identify the challenges, problems and weaknesses when using CAD-systems in design processes to create and improve a methodology (Salehi, V., & McMahon, C, 2011).

According to the studies made by Boedin (2015), students or designers in academic projects do not create CAD-models in the same way or with the same modelling strategy. This leads to decreased efficiency of product development processes because of decreased reusability of models and the ability of designers to work in the same models. In the CAD domain, reusability refers to the ability to which CAD-data can be altered so it can be used or adapted to different applications or designs with minimal effort (Camba, 2016).

COMPUTER-AIDED DESIGN

Computer-aided design (CAD) was introduced around the 1960. CAD is a geometry based approach that has been developed going from two dimensional drawings to three dimensional representations and other manufacturing applications and computer simulations (Krause, Kimura & Kjellberg, 1993). Products can be represented as 3-D solids in a CAD system. The solid part model consists of features and the model can be created by using parameters to define the model. The digital based design can be used in simulations to evaluate properties of the product (Siemens, 2015). Most of the CAD systems have functions that enables design automations. New products are often variations of existing products. One or several sections of design needs to be reused in other designs. Automations can be used to simplify the reuse of existing design data to create new designs (Dassault systems, 2016).

SIEMENS NX

Siemens NX software is an integrated product design, engineering and manufacturing software that helps to deliver products fast and efficiently. The software helps to design, simulate and manufacture products by enabling smart decisions in an integrated product development environment. There are different applications in Siemens NX software that helps in the development process (Siemens, 2015).

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TOOLS FOR ORGANIZING OBJECTS IN NX

A common CAD-method that includes how objects are structured within a part can be created in several different ways with a variety of tools and commands in NX. There are several commands in NX that can be used to structure objects. This section briefly describes the commands Group,

Feature Group and Part Module. Group

The command Group is used to organize and name objects so that it becomes easier to identify them, select them and to edit their display properties. It is possible to group all types of objects such as points, curves, sketches and bodies. A group can be added to another group and objects can be ungrouped from a group without deleting the objects. If a group is deleted, the objects within will also be deleted. The members of a group can be restricted so that they cannot be added to another group. Groups can be created automatically when using options in some commands such as Import Parts, Point Set and Section Curve (Siemens, 2015).

Feature Group

Feature Group is a command in NX that can be used to organize and identify features in named

collections. A feature group appears as an expandable node in the Part Navigator. It is possible to suppress, delete, move and copy feature groups. When deleting a feature group it is possible to choose to also delete its members. A feature can be added to more than one feature group. (Siemens, 2015).

Part Module

The command Part Module allow designers to distribute features in a complex part into groups. It is easier to display and update areas in the complex part which allows designers to focus on a single area. Multiple part modules are created in the main part file. Part modules can be used for collaborations using interpart WAVE references. Each external part module is linked to the corresponding part module in the main part. (Siemens, 2015).

Inputs and outputs in part module can be created using the Define Part Module Input and Output commands. Inputs are selected extractions of the geometry objects and expressions from the part and it isolates the part module from the upstream part. Input objects becomes the parent reference for the features that can be created. The outputs are extractions of the features and expressions and specified from the part module. It isolates the part module from the downstream part. If the part module is inactive then the output are displayed and the other objects are hidden (Siemens, 2015).

Feature properties

Time stamp is the order for which a feature is applied to a body. A time stamp is assigned to each created feature and when a body is modified, the update follows the order of a feature time stamps. The interior topology of a part is changed by moving a feature up in the history tree. The reorder of a feature changes the order in which a feature is applied to a body (Siemens, 2015).

Expressions

Expressions can be used to control the relationship between the features of a part and it can be used to define and control many dimensions of a model. Expressions can be named and you can insert expression names in the formula string of other expressions (Siemens, 2015).

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AUTOMATION TOOLS IN NX

The tools and functions that can be used to automate features in NX are studied in order to obtain a general understanding of the possibilities or limitations for automating features. This chapter describes the tools and functions User Define Features, Wave, Reuse Library, Part Families, Journals, NX Open, Knowledge Fusion and Parametric Modelling.

User Defined Feature (UDF)

User Defined feature (UDF) is a tool that can be used to automate commonly used design elements by creating a NX built-in feature. The UDF can be added to the target model and it is treated as a single feature when it is inserted into the part. If you want to delete or suppress a component in a UDF the entire UDF will be suppressed or deleted. Separate UDF palette can be added to the Resource Bar (Siemens, 2015).

UDFs are created with the User Defined Feature Wizard and are saved as special part files. The files can then be inserted in the Modelling application to later be added as features to a target solid. NX Help Pages describes two steps that is needed to create a UDF. The first step is to create a model for the UDF and the second is to start the User Defined Feature Wizard and save the model into a UDF. When modelling a feature, the feature references should be held to the minimum requirements. When the UDF is inserted into the current part file, a Create dialog box will appear that allows the designer to review and change parameters for the UDF, resolve references and assign the destination (Siemens, 2015).

Wave

There are commands for interpart modelling that enables modification of new geometries or expressions in one part based on the geometry or expression in another part. This can be done in the Modelling and Assembly application and the parts can be associatively linked or non-associatively linked. Wave is an interpart modelling command to link geometry between part files and is typically used with an assembly structure to manage the parts relationships. If the new geometry is associatively linked the geometry and attributes will update if the source geometry is edited (Siemens, 2015).

Reuse Library

The Reuse Library navigator can be used to access and use reusable objects and components in a model or assembly. It is a library of commonly used: User defined features, law curves, shapes and profiles, 2D sections, standard parts, part families and templates. Frequently used objects or features from a model can be saved as a reusable object template in reuse library with the command Define

Reusable Object. The reusable objects are displayed in a hierarchical tree structure in the NX

resource tool reuse library navigator. The tool has a main panel to display the library containers, groups and subgroups and a search panel to search for a specific object or folder. The searches and objects can be saved to either a border bar or a ribbon tab. In order to define a reusable object you just have to identify the object and go through a few steps to save it (Siemens, 2015).

Part Families

The part family command is used when you want to generate a family of similar parts. The command is commonly used to create a library for standard parts. Each member of the family is based on a template part and a spreadsheet. To edit a family member you use the template part and edit the spreadsheet in it. To create a Part family, you start by creating a temple part, an NX part file constructed as a base for the part families. Then you continue by using the template part to create a table in the NX spreadsheet. A table describes the attributes and variable parameters that can be changed in the template part when a family member is created. Part families can only be used in Assembly mode (Siemens, 2015).

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Journals

Journals is used to automate repetitive tasks, procedural workflows, rapid creations of automated tests and to create more advanced automation programs. The tool records, edits and replays interactive NX sessions. Journals can be created automatically by recording an interactive NX session, or manually using text editor. It is also possible to manually edit the session after recordings with simple programming constructions. The supported programming languages are C#, C++, VB, .Net and JAVA. It is possible to modify the program to add general inputs and outputs by turning the journals into applications. Another limitation is that the commands that are supported by journals are limited (Siemens Product Lifecycle Management Software INC, 2014).

NX Open

NX Open is a collection of API’s that enable custom applications for NX. It makes it possible to automate complex and repetitive tasks and to customize the NX interface. Programming languages that can be used are C/C++, Visual Basic, C#, Java, and Python (Siemens Product Lifecycle Management Software INC., 2014). NX Open provides with several benefits such as the ability to customize NX to meet process needs, decrease time by automating complex and repetitive tasks, reduce rework by reusing the best practice of the company and industry and also to maintain the look and feel of NX which reduces user training time.

Knowledge Fusion

Knowledge Fusion (KF) is an API that takes to advantage the engineering knowledge. It is a fully integrated knowledge based engineering (KBE) tool that uses created rules as basic building blocks of the language. KF is used to create powerful applications that is used to capture and reuse design intent to speed productivity while controlling change propagation (Siemens Product Lifecycle Management Software INC., 2014). These rules can be used to standardize design processes and to ensure that requirements are fully understood and met. (Siemens Product Lifecycle Management Software INC., 2014).

Parametric Modelling

Parametric modelling is used to control the behaviour of the geometry by adding dependencies between expressions. Variations of the geometry are accomplished by modifying the values of the parameters. When using parametric modelling it becomes possible to make modifications without deleting or re-creating any metrical components (Salehi & McMahon, 2011). This way of facilitating the changes of geometries does not require knowledge in different programming languages. The concept of parametric modelling is however often utilized in programming.

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3 Method and Implementation

The process and the methods that were used to conduct this master thesis are described in chronological order in following chapter. The first part of the chapter describes the process that was used through this project and is then followed by a description of each phase and method. The description of the methods includes information about how they were used in the project and why.

PROCESS

The development process of this thesis was based on Human-centred design. Human-centred design is an approach to system development which aims to make the systems useful and usable by focusing on the user, their needs and requirements (ISO 9241-210:2010). This approach also enhances effectiveness and efficiency of the system. In order to create a CAD-method with a human-centred approach the process in this thesis was influenced by the User-Centred Design (UCD) principles and processes that are described by Jokela (2002). This model identifies five UCD activities:

 planning of human-centred design

 understanding and specifying the context of use  specifying the user and organizational requirements  producing design solutions

 evaluating designs against requirements.

The development process in this thesis included the phases; project planning, literature research context immersion, analysis, ideation and detail design. The phases are presented in Figure 3. During the first phase, project planning, the task was clarified and the project was planned. The second phase, literature research included studies of theories and research in relevant areas of the project. During the next phase, context immersion, information about the context, user and their needs were gathered in order to understand and specify the context of use. The fourth phase, analysis, intended to present a profound understanding of the work process in the different CAD-methods. During the next phase, ideation, new design solutions were produced. The final phase, detail design, allowed finalization of the solution in this master thesis. The process also included a literature research that was ongoing through the whole project.

Figure 3. The phases in this thesis project.

Project

planning Literature research immersionContext Analysis Ideation designDetail

Clarifying the task and planning the project. Gathering information about the context, users and their needs. Analysing and presenting a profound understanding of the work process in the different CAD-methods. Producing solutions for the problems. Finalizing the result of the thesis. Studying theories relevant to the project.

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According to Ulrich and Eppinger (2011), it is important to choose the phases and deliverables of every phase wisely in order to assure the quality. Cooper (1990) states that a stage-gate model can control the overall development process in the project. The stage-gate model was used in this thesis to improve and control the result of the process. The process was divided into a number of stages with checkpoints as gates. The gates are listed in Appendix 1.

PROJECT PLANNING

The first phase of the master thesis was to create a plan for the project. The assignment for the project was studied and the background was analysed. This information was used to identify the different phases of the project. The methods in the phases were planned and a Gantt chart was created to schedule and visualize the time distribution for each phase. The established project plan was used to guide the project members towards the defined goal of this master thesis. The time schedule of this project is presented in a Gantt chart in Appendix 2.

LITERATURE RESEARCH

The literature research included studies of theories and research in the project area by looking at previous master theses and peer-reviewed articles and printings. The first part of the research was to study previously completed master theses similar to this project; with focus on automating features or organizing work within a CAD-program.

The second part of the research was to look for information about the objectives and the purpose of creating and implementing a CAD-method. The goal was to find answers to the reasons of having a common CAD-method. The third part of the research was to find reliable strategies that could be implemented in the development process.

The last part of the research was to look at the possibilities in NX to organize objects and automating features. The goal was to obtain an overall picture of the variety of tools that the product development software provides for organizing or automating. The information was used to get inspiration and to frame both areas.

The research areas in this project were:  methodology objectives

 organizing tools in NX  automating tools in NX.

CONTEXT IMMERSION

During this phase, information about the context, users and their needs were gathered. The purpose was to understand each Tool CAE-analyst’s CAD-method and to find frequently used features that they use. In order to gather this information, six Tool CAE-analysts were observed of which three of the observed Tool CAE-analysts were interviewed. Four of the observed analysts used the CAD software NX and the other two used CATIA V5.

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Contextual Inquiry

In order to understand the situation and to get an overview on some of the various work methods, the Tool CAE-analysts were observed one by one. The observation was performed according to the contextual inquiry approach, which is a process that is meant to improve the understanding of the user in order to design for the user. The approach is said to create reliable knowledge about what the users do and what they care about (Beyer & Holtzblatt, 1999). The contextual inquiry was prepared by deciding what evaluation questions there were to find answers to. The evaluations questions are presented in Appendix 3. Contextual inquiry was done by talking to the Tool CAE-analysts in their workspace while they worked on a real task. The Tool CAE-CAE-analysts were asked about their actions, step by step, for us to understand the details and the motivations for their actions. The work that the Tool CAE-analyst performs is complex and there are many details to observe and a lot of information to take in. In order to cover all the important details the observation was recorded. Recordings of their work with a screen recordering program enabled the possibility to go back and go through their work. The free software Rylstim was used to record and it was installed on their computers before the observations.

Each observed method in NX was saved with a copy of the model file. The recordings and files were then analysed after the observations to document each CAD-method with details about the main steps to solve the task, the used commands and the structure. The documentations and the recordings were used through the whole project process to look for details and to be reminded of information.

Interviews

Each Tool CAE-analyst was interviewed directly after the observation. The intention was to gather more information about the users’ needs and what they think is important. The interview questions, presented in Appendix 4, were semi-structured. Semi-structured questions allows the participants to talk freely about the asked question and to come with unexpected answers about thoughts and what they think is important (Lantz, 2007). The semi-structured interviews enable qualitative data which allows a decreased number of participants (Krag, 1993).

A test interview was performed before the actual interviews started. This gave another person's point of view on the questions and enabled a chance to enhance them before the actual interviews. The interviews were held in their work environment in order to promote the interview. A brief introduction about the study, how the interview will be documented and how long it will take was given before each interview. The first questions were about pure facts and the following questions followed a chronological order. After the interviews, a summary was given to the participants where the answers were repeated. The summary was done to check if the participants were understood correctly. If the repeated answers were the same then the results became more reliable. All interviews were documented with writings during the interviews. The Tool CAE-analysts’ needs were summarised along with a list of predetermined standards that they must use.

ANALYSIS

Each observed Tool CAE-analyst’s CAD-method and work were evaluated in this phase in order to develop a profound understanding of the methods. The purpose was to find the essentials to include in a common CAD-method and to find where in the process it could gain the most to develop and implement automated features.

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The first step in this phase was to study each Tool CAE-analysts’ CAD-method one at a time to define the distinctive ways of organizing objects in a CAD-method. The way of grouping and naming objects were noted and then compared with the rest of the CAD-methods to discover advantages and disadvantages. The Tool CAE-analysts work were then analysed to find the common denominators in their work and to find frequently used features. The purpose was to highlight operations in their work that would be beneficial to automate. The last step in this phase was to analyse the CAD-method that the Tool CAE-analysts use in CATIA V5 to see how they organize their work and when they use the already developed automated features. The automations were further studied to understand what they do and how they work.

Hierarchical task analysis

The observed Tool CAE-analysts’ CAD-methods in NX were each presented in Hierarchical Task Analysis-models. HTA is a method to analyse a high level task by decomposing it into a hierarchy of subtasks (Hornsby, 2010). The method makes it possible to structure, compare and understand different operations (Stanton, 2006). The HTA-models can be used to explore and compare various possible approaches to completing a similar task (Hornsby, 2010). The CAD-methods were represented in HTA-models to visualize the order that operations were conducted in and to understand how the Tool CAE-analysts organize objects. The HTA-models also included which commands the Tool CAE-analysts used in NX and a copy of the Part Navigator.

Analysis of the Tool CAE-analysts’ CAD-methods and work in NX

The HTA-models were studied to learn each Tool CAE-analyst’s strategy when they complete a task. Each strategy were then evaluated to discover the essentials to include in the common CAD-methods. The CAD-methods were then analysed to determine the most suitable way of organizing. The structure in each CAD-method were therefore studied to see how objects are organized and named. The structure of each CAD-method was then compared with the others to evaluate the advantages and disadvantages with each way of organizing objects. Each CAD-method’s way of structuring objects were also evaluated by going through the groupings and naming’s of objects within the Part Navigator. The analysis of the CAD-methods is presented in Figure 4.

Figure 4. Analysis of the CAD-methods that are listed in HTA-models.

The operations in the different CAD-methods were analysed to find frequently used commands and operations. This analysis was used to analyse operations that would be beneficial to automate and to understand the commands used in the operations.

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Analysis of CAD-method and automations in CATIA V5

The CAD-method that the Tool CAE-analysts’ use in CATIA V5 was analysed by studying the material that was gathered from the observations and interviews in the previous phase. The way to organize objects in groups and how they name objects was documented. The CAD-method was also studied to find the factors that makes the CAD-method approved and used by all Tool CAE-analysts that uses CATIA V5. The automations in CATIA V5 were studied by analysing them one at the time. A Tool CAE-analyst demonstrated how each automation work and how it is used.

IDEATION

The ideation phase was divided into two sessions and the two sessions followed three steps. The steps are presented in Figure 5. The first step was to create ideas for automations and ideas for what to include in a common CAD-method with Brainstorming. The second step was to develop these ideas and to create a common CAD-method with the users. This was done in two different future workshops, one for each session. The final step was to develop a first draft of suggested automated features and a first draft of a common CAD-method.

Figure 5. Describing the two sessions in the ideation phase. Brainstorming

A brainstorming session is described as a method used to generate solutions to problems (Osborn, 1953). Brainstorming was used to generate ideas for features to automate in NX and to come up with ideas on how to organize objects in a common CAD-method. The brainstorming was carried out in two sessions: one to come up with ideas on automated features and one to come up with ideas for the common CAD-method.

The brainstorming sessions followed some of the explicit set of rules that was set up by Paulus and Brown (2003). The first rule is to set the goal of the session to aim for quantity, not quality. The second rule is to forbid negative critic of all kind. The third is to unleash the free mind and welcome wild and different ideas. The fourth is to permit the participants to modify others ideas. Building

Step 1. Brainstorming •Create ideas on

automated features

Step 2. Future Workshop

•Develop the ideas on automated features with the users

Step 3. Concept development

•Create a list with suggested features to automate Step 1. Brainstorming •Create ideas on a common CAD-method Step 2. Future workshop •Create a common CAD-method with the users Step 3.Concept development •Create a concept for a common CAD-method

Session 1. Automations

Session 2. CAD-Method

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on others ideas or by combining ideas, the boring or the crazy ideas can be the one that leads to new ideas that leads to a solution to the problem. The fifth rule is that the participants can ask for brief clarifications if they don´t understand an idea, abbreviation, or term. The last rule is that only one person can speak at a time, if someone has an idea while someone else is speaking, the idea is written down on a sticky note.

The brainstorming sessions started with a warm-up exercise that is said to reduce anxiety. The warm-up exercise is called word association and is an exercise where you give the participants a random word and ask them to come up with as many associations as possible (Wilson, 2013). The method “brainstorming with the help of sticky notes” was then used for each brainstorming session. The method is about writing down ideas on sticky notes that are easy to move around and to sort. The method starts by formulating and writing down a question for the brainstorming. Ideas where then individually written down on sticky notes until the creativity dried out. Every sticky note is then placed up on a board and the ideas are grouped and named with a suitable heading, Figure 6. The last step of the method is to make combinations of the ideas and to come up with new ideas. When the brainstorming was over, the last step was to do an evaluation. The ideas that had most potential was marked and divided into two categories: can be used immediately or interesting but has to be further developed.

Figure 6. Sticky notes placed on a board to be categorized. Future workshops

The method future workshop was used to decide the details for how the automated features will work and to create a first draft of a common CAD-method. Future workshop is a method for planning and forming the future. The method followed Vidal’s five phases; preparation phase, critique phase, fantasy phase, implementation phase and the follow-up phase (Vidal, 2006). Due to constraints only phase one to four was used in the workshops. Two separate future workshop sessions were conducted. The objective of the first one was to develop the ideas on how the features will work and the objective for the second one was to develop a first draft of a common CAD-method. All the phases in the workshops are described in Figure 7.

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Figure 7. The phases in the future workshops sessions.

In the first phase of the future workshops, preparations of methods, rules, local facilities and the timetable were settled. Every Tool CAE-analyst that works in NX was invited to participate in both sessions. The invitation included a schedule, information about the location and a brief introduction about the purpose and principles of the future workshop. The time for each sessions was set to 2.5 hour and the location was chosen in consideration to Vindals (2006) recommendations; to choose a location that is suitable adapted to the group with a cosy, informal and inspiring atmosphere. In the second phase, the critique phase, the participant got to specify issues and problems to enable a critical understanding of the problems in question (ProWork, 2009). Before entering the second phase, the participants first got to perform a warm-up exercise and then they got introduced to a question of a problem to solve. The first session had the question “What problems can occur in the automations?” and the second had the question “What are the problems that can exist with structure and naming in a CAD-method?”

In the critique phase of the first future workshop session, the participants got to highlight problems that can occur with the suggested automated features when it comes to how they work. The list with ideas on automated features was printed out and attached on the walls. The participants got to go through the ideas one by one and write down every problem they could think of on sticky notes and post them on the wall next to the automated feature, Figure 8.

Figure 8. The participants in the first workshop session during the critique phase.

Pr

ep

er

at

ion

Rules, local facilities and timetable were setteled An invetation was sent out

Cr

it

iq

ue

Warm-up _excercise Generate critical points on how the automated features will operate Generate critical points with a common CAD-method

Fan

ta

sy

Find soulutions _{to the critical}

points, without thinking of constrains

Im

plementat

ion

Develop ideas so that they become

implementable Choose ideas Document concepts

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In the critique phase of the second future workshop session, the participants got to write down problems that can occur in a CAD-method. The participants were teamed in groups of two to discuss and come up with critical problems.

The next phases for the future workshop sessions was initially planned to be two separate phases, the fantasy phase and the implementation phase. The intention of the fantasy phase was for the participants to come up with solutions to the critical points by creating ideas for how to solve them. It was important that no one reflected about constrains, traditions or other barriers when generating solutions to critical points. The intentions in the implementation phase was to evaluate all ideas with regard to realistic conditions and to further developed ideas so that they became implementable and to select the most promising ideas. The second phase took more time than planned and because of the short amount of time that was left, the third and the fourth phase was combined into one last phase in both future workshops.

In the last phase of the first session, the participants first got to describe the critical points that they had written down on sticky notes. Then they got to work together to discuss and find ideas that solved the problems. The ideas to solve the problems where discussed and the best ways to solve the problems was chosen and written down.

In the last phase of the second session, the two teams got to go through the problems that they had listed that they believe could cause issues in a CAD-method. Then the teams got to come up with ideas that could solve the problems.

A first draft of a concept for a common CAD-method was created based on combinations of ideas from the brainstorming session, new ideas from the future workshop and the Tool CAE-analysts’ opinions from the future workshop. Tool CAE-analysts development process was divided into sections and the order to perform each section was decided and described in the first draft of the common CAD-method. The concept also included how to organize and name objects.

The brainstorming resulted in a list with ideas on features to automate. The list was edited after the future workshop. Some ideas was further developed, some ideas was removed from the list and new ideas from the future workshop was added to the list. The list contained information about the purpose with every automation and how they can work.

DETAIL DESIGN

The last phase in the project was to develop the concept of the CAD-method into the final drafts and to create a manual with instructions on how to follow the CAD-method. The last phase also included development of the list with automations into a final draft. The list was further analysed to ensure that the automation could give the desired result. Information that described the commands that could be used in the automations was added to the list. The list was also completed with information about parameters that are important to include and parameters that need to be adjustable.

The commands in NX that can be used to organize object were further studied to see how they work, what functions they have and to understand the settings. The commands were then tested to see if they could be used to structure the CAD-method. The first command that was studied was the command Feature Group. A template was created with organized and named feature groups. The template is meant to be used by the Tool CAE-analysts to structure their features in the Part Navigator.

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To develop the first draft of the common CAD-method and the template into a final draft a tool concept was created. The tool concept was created by following the CAD-method and by using a copy of the developed template. Changes were made to the CAD-method and the template during the test to create the final draft. Every step that was needed to create the tool concept was documented and the documentation was then used to create a manual with instructions. The manual also includes information about how to structure the work with naming and groupings. The steps to create the final draft of the common CAD-method, a template and the manual are presented in Figure 9.

Figure 9. The steps to create the template and manual are described in a chart.

The command Group was then studied and tested to see how it could be used in the CAD-method to easily show a selected group of objects. The command Layer was then studied to see how it could replace the Group command. The command Layer was evaluated to find the advantages or problems that could occur. The last command that was studied was Part Module.

The automations that was developed during the ideation phase were analysed to see if it was possible to create the desired results and to find a solution that works in all projects. Different commands were tested until the desired results were created. The commands and the settings that generated the result were then documented. The parameters that are important to include and parameters that have to be adjustable was also documented. The list with the automations from the ideation phase was completed.

Studying commands in NX.

Creating a template with the command Feature Group. Creating a tool concept by following the CAD-method and using the template.

Making changes to the template and the CAD-method. Creating a manual with instructions.

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4 Result of Context Immersion

This chapter presents the results from the context immersion phase. The chapter starts by presenting the work process and follows with a presentation of the users’ needs and the standards in their work. The important outcomes of the observations are presented in Appendix 5. The results from the interviews are presented in Appendix 6.

THE TOOL CAE-ANALYSTS WORK PROCESS

The steps described in this section are the general steps that the Tool CAE-analysts performs in each project. The Tool CAE-analyst starts by creating a setup for the tool concept. The setup is built with surfaces for upper half of die, lower half of die, movable pads, blank, pins and holes. The first step when creating a tool concept is to import, rotate and translate the customer CAD solid according to coordinates found in the PA. The surface of the upper half side or the lower side of the customer CAD is extracted and used to create extended tool surfaces. The extended tool surfaces of the customer CAD are then used to create lower and upper half of tool surfaces. Figure 10 presents an example of a customer CAD in blue and the extended tool surfaces in yellow.

Figure 10. Tool surfaces in yellow for a B-pillar.

The next step is to create movable pads. Movable pads are used to form the product in different sequences. Each movable pad is given an individual stroke length. The number of movable pads varies and depends on size and on the design of the products. The parts in the setup are named with specific PID names and are assigned with a specific colour. Standards for naming and colouring of parts are shown in Appendix 7. Split lines are created and used to create split surfaces to split the upper half of the tool surface or the lower half of tool surface into a movable pad. Figure 11 shows an example of a complete setup for a tool concept. It consists of upper half of tool surface and lower half of tool surfaces, movable pad, blank and pins.

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Figure 11. Example of a setup of a tool concept.

The last step is adding blank centrings and creating holes in the blank. The geometries for the holes can be shaped to be round, slot or as a dog bone as shown in Figure 12.

Figure 12. The first sketch is for a slot shaped hole and the second is for a hole shaped as a dog bone.

When the tool setup is created, two other preparations has to be completed before the simulation can run. The first is meshing the tool and blank and the other is creating an input file containing material models, strokes and forces of the movable pads. The result from the simulation highlights thinning and thickening/wrinkling areas of the simulated blank.

The parameters that can be changed to improve forming results are:  press direction

 part geometry

 position of centring pins

 local blank holders over the pins  shape of the blank

 tool surface

 adding/removing movable pads  split lines for movable pads  forces on movable pads

 gaps between movable pads and solid parts  the stroke length for movable pads.

upper half of tool surface

lower half of tool surface

blank

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Thickened areas can be improved by forcing the blank to stretch out. A way to stretch the blank is by adding a draw bead to the tool surface outside of customer design. When the simulation shows acceptable result, the tool setup is packed in the TS together with split curves, nominal curves and an out of die model. The nominal curve is the same as the contour of the customer CAD. The out of die model is created from the contour of the hardened blank. The contour of the press-hardened blank is named nod curve.

NEEDS TO TAKE INTO CONSIDERATION

The Tool CAE-analysts needs that has to be taken into consideration are listed and described in this section.

 They need to be able to perform and complete all steps described in section 4.1.

 They need to be able to decide the order to do each step and to choose which commands in NX that they prefer to use. It is also essential that they can vary the content in the tool concept to fit the current project that they work on.

 The customer CAD has to be easy to identify in a tool concept. The first reason is that they need to be able to ensure that it fits between the upper half of tool surface and the lower half of tool surface that is created. The second reason is that the customer CAD can be updated several times during a project and a need is therefore to compare the old version with the new version to identify geometry changes. Large modification do not always occur in a new update of a customer CAD and the old tool concept can in most of the cases be modified to fit the new update.

 They need to be able to identify the generated features in a CAD-model and important parameters. The reasons are to easily make changes to parameters in order to improve forming simulation results and to understand another Tool CAE-analysts CAD-model in order to continue with their work instead of restarting from scratch. The parameters that are important to identify are:

 rotation parameters to positioning the customer CAD into CAR CSYS coordinates

 stroke lengths of tool parts  diameter of pins

 thickness of the customer CAD.

 They need to save all created versions of tool setups and blanks in the CAD-model in order to compare forming simulations with the tested tool setups and blanks.

 They need to be able to identify which tool setup and blank that generated the best forming simulation result and which parts in the CAD-model that has been exported to the tooling department of Gestamp HardTech.

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STANDARDS IN THE TOOL CAE-ANALYSTS WORK

There are standards in the work process that the Tool analysts at DTC follows. The Tool CAE-analysts rotates and translates the customer CAD to predetermined coordinates that they find in the PA. The Tool CAE-analysts creates two upper halfs of the tool surfaces, one for when the tool is in closed position and one for when the tool is in open position. The upper half of tool surface is created with an offset at the same distance as the thickness of the customer CAD.

A standard when creating a movable pad is to creates two split surfaces. The first split surface has to be within 2 mm of the customer CAD area and the second surface has to be at an offset of 1 mm from the first split surface. The first split surface creates the movable pad and the second split surface creates a clearance.

All the holes for the pins must be created on the blank. The collar and the hole for the dog bone must be created on the out of die model. The radius of the flange must be 3 mm high and the inner radius must also be 3 mm. Figure 13 shows a collar on the out of die model. There are more standards of the pins and holes that needs to be considered but are left out intentionally do to company confidential.

Figure 13. Examples of collars created on the out of die model.

Some projects includes a patch and there are standards that needs to be followed when creating a pocket in the upper half of tool surface for the patch. There must be a clearance of 6 mm between the patch and the upper half of tool surface and there must be a radius of 3 mm in the patch pocket.

Development of a new CAD-method for Tool CAE-analysts at Gestamp HardTech

MASTER'S THESIS